Spark arrester



Jan. 23, 1962 E. K. KRUCKEWITT SPARK ARRESTER Filed Jan. 12, 1960 INVENTOR.

Edward K. Kruckewi BY Q W a W Attorneys t nice iifil'ifi i Patented Jan. 23, 1962 3,017,954- SPARK ARRESTER Edward K. Kruckewitt, 433 North t., Woodland, Calif. Filed Jan. 12, 196%), Ser. No. 1,944 1 (Zlaim. (fill. 183-74) This invention relates to chimney spark arresters and more particularly to spark arresters of the screen type.

Heretofore, the art devoted to chimney spark arresters has been mainly concerned wtih screens placed across a chimney flue either at the upper opening thereof or elsewhere, and comprising sheets of wire mesh material either transversely disposed with relation to the issuing stream of smoke and hot air, or otherwise arranged as in combination with another screen or with a solid cover plate or baflle element transversely so disposed.

In such latter arrangements, the solid elements interfere with the draft of the flue, and the manufacturing process entails the complicated assembling and fastening together of a large number of separate elements, the completed device often having structural and mounting weaknesses when subjected to strong lateral wind forces.

Most of the screens of the art have a tendency to collect and to build up deposits of soot, particularly in areas thereof exposed only to uni-directional, usually upward, smoke currents; and these deposits, besides clogging the screens, constitute fire hazards. In much the same way, sparks and embers carried by the smoke currents and caught by the inner surfaces of such areas are maintained by the smoke currents in these caught positions for considerable periods, causing burning and eventual destruction of the device and constituting further fire hazards. Also the screens of such devices are often closely exposed to the intensely heated air and even the flames of the fire below, and no effective provision is made for cooling them While the fire is burning.

It is therefore an object of the invention to provide a chimney spark arrester having reduced exposure of the parts thereof to heat and flames from the fireplace, and having special provision for the cooling of all parts as by ambient lateral wind and air currents.

It is another object of the invention to provide a chimney spark arrester arranged for the automatic cleaning away of soot therefrom and the immediate rejection of sparks and embers from all parts thereof as by ambient lateral air currents.

It is still another object of the invention to provide a structurally strong and solid spark arrester as above described and having a minimal flow restricting area exposed to lateral wind forces, and including improved means for mounting and affixing the device upon a chimney and retaining it thereon against the action of the wind.

It is a further object of the invention to provide a spark arrester as above described and adapted for manufacture from a minimum number of parts and by simple and economical processes, the materials being inexpensive and easy to obtain.

It is a still further object of the invention to provide a spark arrester as above described and imposing minimal obstruction to the smooth and uni-directional flow of smoke currents upward from the chimney flue.

It is still another object of the invention to provide a generally improved chimney spark arrester.

Other objects together with the foregoing are attained in the embodiment described in the following description and shown in the accompanying drawings in which:

FIGURE 1 is a perspective view of the spark arrester of the invention, mounted over the upper flue opening of a chimney; and

FIGURE 2 is a median vertical section, to an enlarged scale, of the spark arrester elements and flue tile shown in FIGURE 1, the plane of section being indicated by the line 22 in FIGURE 1.

t will be understood that the chimney spark arrester of this invention is susceptible of numerous physical embodiments depending upon the particular environment and requirements of use therefor, and the scope of the invention is to be understood as not limited except as described in the appended claims.

The spark arrester of the invention, generally indicated in the drawings by the reference numeral 11, is shown as mounted on the top of a chimney 12, the chimney in this example having an upwardly opening flue and flue opening 13 defined by a tubular or hollow tile member 14, the member 14 being generally rectangular in plan View and formed with end walls 16 and 18, as well as side walls 17 and 13.

In accordance with the invention, a mounting means including an adjustable spreading clamp generally designated by the numeral 21 is disposed in outwardlydirected clamping engagement with the opposite side walls 17 and 19 of the chimney tile member. The clamp 21 includes an elongated metal bar 22, the bar being normally downwardly bowed with respect to the chimney, as appears most clearly in FIGURE 2, to establish a bias condition in the bar favoring resilient lateral or downward bowing or distortion, rather than mere longitudinal distortion, when the bar is subjected to compressive end loads.

As here shown, the bar 22 is bowed in two respective manners, i.e. gently downwardly from the extremities toward the median plane of the bar, and also sharply and acutely adjacent the median plane, as by formation of a downwardly convex U-shaped offset portion 23 therein. The portion 23 provides for minor resilience and major adjustment of the bar to fit widely varying widths of chimneys, and the gently-bowed formation provides for minor adjustment and extra resilience in fitting the clamp into clamping engagement with the chimney side walls 17 and 19.

The clamp 21 also includes upstanding end portions 26 and 27 formed thereon for bearing against the interior surfaces of the walls 17 and 19 and for forming an attachment to the other portions of the spark arrester. Mounted on the portions 26 and 27 and laterally and outwardly extending therefrom, is a pair of oppositely projecting members or studs 28 and 2?, respectively, adapted for hearing against the subjacent top surfaces of the respective side walls 17 and 19, for supporting and aligning the spark arrester upon the chimney top and for limiting the penetration of the spark arrester into the flue opening 13.

As shown in the drawings, more than one clamp 21 may be used, and two are shown. The second clamp is substantially identical to the first in structure and purpose and therefore is not described in detail.

The spark arrester 11 also includes a perforated concave-convex cover member 31, preferably made of screen material and formed with a peak portion, here defined by an upper ridge line 32, a pair of side walls 36 and 37, and end walls 38 and 39 extending downwardly from the peak to define an interior cavity and a bottom o ening 41, the latter being formed to match the chimney flue opening 13. The cover member 31 is fitted on the chimney over the flue opening 13, with the cover member walls 36-39 extending to the top surfaces of the respective chimney tile member side and end walls 1619 and with the opening 41 in substantial registration with the flue opening 13.

The cover member cavity, opening downwardly into the flue, receives the discharge of the chimney and passes substantially everything, except the larger embers, through the screen material of the member. It will be readily seen that this arrangement provides for disposition of the screen material at a location considerably removed from the heat and flames of the fireplace, and that the generally upwardly protruding disposition of the screen material provides for ready and effective cooling of the screen material, as by laterally circulating ambient wind and air currents. In comparable fashion, larger glowing embers and, in particular, large pieces of burning paper restrained by the screen are either cooled below the char point or are quickly consumed owing to the additional oxygen provided by the moving air current. The extent of burning and the manner of impingement of the embers against the screen governs whether or not the embers will be consumed or be put out. In either event, the screen prevents escape of the larger embers and the free movement of the air keeps the screen material cool, a factor which provides a long-lived device.

As a further important feature of the invention, the formation of the cover member 31 with an upper peak portion and with the walls 36-39 extending downwardly therefrom has the effect of insuring that the walls 36-39 are all inclined substantially from the plane of the horizontal, and consequently these screen material walls are everywhere aligned for and exposed to the lateral (generally horizontal) wind currents for transverse passage of the wind therethrough. In other words, in the structure of the invention there are no horizontal walls, either of screen or solid material upon which soot and embers transported by the upward draft of smoke can tightly lodge or become entrapped. With the walls disposed at the steep slope indicated, the wind currents have optimum effect in dislodging or cleaning away soot and embers and rejecting such particles inwardly into the cover member cavity.

In a preferred form of the invention, as shown in the drawing, the cover member 31 is formed with the walls 38 and 39 thereof constituted as opposed vertical end walls of triangular shape. The walls 36 and 37 are formed as rectangular side walls joined at the upper edges (i.e. along ridge line 32), the walls 36 and 37 being joined at their lateral edges to the lateral edges of the walls 38 and 39, as at margin lines 46, 47, 48 and 49 extending downwardly from two spaced ends or points 51 and 52 of the ridge line 32. The clamps 21 are arranged to extend from the lower extremities of the screen walls 36 and 37 across the bottom opening 13, the upstanding portions 26 and 27 of the clamps having inclined tip portions 53 and 54 conforming to the slopes of walls 36 and 37 and being secured thereto as by fasteners 56. This arrangement provides a triangular cross-section for the spark arrester and lends structural strength and solidity thereto for resisting the disruptive forces of the wind, while at the same time presenting a minimal surface area for the impingement of these forces, the cross-section of the wire screen forming but a minute fraction of the total area of the screen walls.

As a further feature of the invention, the structure as described is adapted for inexpensive and economical manufacture as by formation of the cover member 31 from a single sheet of screen material by redoubling and folding processes, wherein pairs of lateral edge portions 56 and 57 are brought into meeting engagement and are secured together in seams as by fasteners 58. In the particular form as shown, the cover member 31 is formed by folding the sheet of screen material along the ridge line 32 and along the lines 46-49, the lateral edge portions 56 and 57 being seamed or overlapped along the vertical center lines of the end walls 38 and 39. Stiff vertical reinforcing members 61 and 62 are secured to the joined edges as by the fasteners 58 and add to the rigidity of the structure.

It will be apparent that the invention as described above and in the claim may also be formed to pyramidal. conical and other shapes without departing from the spirit and scope of the invention.

What is claimed is:

A spark arrester for use with a chimney having a pair of opposed side walls and a pair of opposed end walls defining an upper opening of predetermined form, said spark arrester comprising: a concavo-convex cover member formed of screen-like material, said member including a pair of triangular end walls each having a base located substantially coincident with the corresponding one of said pair of chimney end walls and extending vertically upwardly to a central apex located at an altitude at least one and one-half times the length of said base, said member further including a pair of sloping side walls each projecting outwardly and downwardly from a peak extending between said apices of said triangular end walls to a location substantially coincident with the corresponding one of said pair of chimney side walls; and a spaced pair of adjustable spreading clamps each including an elongated metal bar secured adjacent the extremities thereof to the opposite of said cover member side walls, each of said bars being downwardly bowed for resilient compressive engagement with the adjacent one of said chimney side walls; and a pair of studs mounted adjacent the extremities of each of said bars and projecting oppositely outwardly for supporting engagement with the adjacent top of said chimney side walls and for limiting the penetration of said spark arrester into said chimney opening.

References Cited in the file of this patent UNITED STATES PATENTS 1,438,868 Shull et al. Dec. 12, 1922 1,572,925 Harteau Feb. 16, 1926 1,585,714 Howard Mar. 25, 1926 1,709,884 Slocum Apr. 23, 1929 1,879,289 Johnson Sept. 27, 1932 2,718,278 Sargent Sept. 20, 1955 

